There is a substantial need for machines that are capable of high speed, high quality addressing of discrete media elements, such as envelopes, cards, flats, newspapers, or the like. When media elements are directly printed rather than having address labels applied thereto, they present a much better appearance. The appearance alone may be the difference between a recipient discarding the media without even examining it carefully, or responding to the media element. The quality nature of the print also is important in order minimize postage since the printing of bar codes on media (which must be printed in a high quality manner to be effective) speeds delivery of the media and may significantly reduce postage.
According to the present invention, machinery is provided which is capable of providing high speed, high quality addressing. Utilizing the machine according to the present invention, it is possible to print near letter quality media elements at up to 10,000 per hour, and letter quality elements at up to 6,000 per hour. The media handled can be anything from 3.times.5 inches up to 121/4.times.24 inches and from less than 0.007 to 0.125 of inch thick. The print area may be adjusted within a wide range so that it is properly positioned on the media, depending upon the size and composition of the media, and is capable of printing a complete address, including the postal bar code.
The desirable results are achieved according to the invention by utilizing ink jet printers which are positioned above transport belts which move the media therepast at a high speed. The ink jet printers are mounted so that the orifices thereof will not be clogged by rebounding ink particles, yet there is no necessity for a wiper for wiping ink particles off of the print heads. The feeding and transporting system in a machine according to the invention positively feeds each of the individual media elements to and past the print heads in a precisely controlled manner so that the printing is in a uniform position on the media elements, and so that there is no slippage between the media elements and the transport mechanisms that could otherwise cause blurring or other non-uniformities in the printing quality.
Media elements are fed from a substrate by first and second feed rollers to a pair of pinch rollers and then onto a plurality of endless transport belts having transport wipers holding the edges of the media elements in positive contact with the transport belts. The first feed roller feeds the media element to the second feed roller, which in turn feeds the media element to the pinch rollers. Once the media element is between the second feed roller and the pinch rollers, operation of the first roller is terminated to ensure no double feeding. A selector bar -- the position of which is adjustable with respect to the second feed roller in order to accommodate media of different thickness -- is positioned above the second feed roller and, in parent application Ser. No. 07/596,040, has an abrasive strip thereon which will engage the media elements and ensure singulation thereof to the second feed roller.
In accordance with this continuation-in-part application, a plurality of O-rings are mounted in axially spaced positions along the selector bar and protrude radially into correspondingly located, mating grooves formed axially along the second feed roller. This new feeder arrangement operates in two modes. For thicker media, it operates in a very similar manner to the feeder disclosed in the above identified parent application, as well as in commonly assigned U.S. Pat. No. 4,858,907 (the totality of which is also incorporated herein by reference). In other words, the O-rings perform essentially the same function as the abrasive strip in that they hold back the leading edge of the piece of media next to the bottom of the stack while the bottom piece is fed.
For very thin media, however, the O-rings perform in a superior manner in comparison to an abrasive strip. This is particularly true with respect to media even thinner than the thinnest media that the U.S. Postal Service will accept (0.007 inch). Generally, once two or more pieces of media have simultaneously passed the abrasive strip, all will be fed, and here is where the second mode of operation of the O-ring arrangement has its greatest beneficial effect. When the selector bar containing the O-rings is adjusted downward toward the grooved rubber feed roller beneath it, a series of bends are set up across the width of the media being fed. The associated retarding friction between the O-rings and the piece of media which is next to the bottommost piece is greater than the friction holding the two pieces together. The driving friction between the feed roller and the bottom piece of media is also greater than the friction holding the bottom two pieces together. As a result, the bottom piece is fed by itself and the next piece is held back by the O-rings.
The remainder of the machine construction is as described in parent application Ser. No. 07/596,040, to which reference is made for a complete understanding thereof.
In accordance with this continuation-in-part application, therefore, the present invention comprises, in its broader aspects, a feed control system for feeding printable sheets into a printer, the system including a sheet feed bin having an opening therein and a feed roller positioned in the opening, the improvement comprising: a normally non-rotatable selector bar located above the feed roller defining a sheet gate therebetween, the selector bar having a plurality of resilient, annular rings axially spaced therealong for frictionally engaging and holding back a sheet stacked on an underlying sheet being fed.
In another aspect, the invention relates to an envelope feed control system for feeding envelopes into a printer, the system including an envelope feed bin, the bin including a bottom surface sloping downwardly in the direction of desired feed and an end wall extending vertically above the lower end of the bottom surface, the bottom surface including an opening therein proximate to the lower end, a feed roller positioned in the opening, the feed roller having a plurality of peripheral grooves axially spaced therealong; a non-rotatable, unitary, rounded control surface below the end wall and above the feed roller, the control surface and the feed roller defining an envelope gate, the gate being dimensioned to permit passage of one envelope at a time, and the control surface having a plurality of resilient friction rings thereon, the friction rings located to protrude into corresponding ones of the peripheral grooves in the feed roller, whereby envelopes may be fed singly through the gate and the envelope above the one being fed will be prevented from moving by frictional engagement with the plurality of O-rings.
Additional objects and advantages of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.